Thermostatic device and means for mounting same

ABSTRACT

A thermostatic device including a housing containing a bimetallic disc or strip which engages a cruciform shaped member, the cross arm of which engages a pair of pins which bear against leaf spring-type movable contact arms while the stem of the cruciform shaped member can form reset means providing a simple means for resetting the disc. Means for mounting the thermostatic device include a plate supporting a plurality of springs, each spring in turn urging a housing of the thermostatic device in a direction away from the plate of the device so that when the plate is secured to a surface the temperature of which is to be sensed, the springs urge the thermostatic housing into contact with the surface.

United States Patent 1 Pringle et al.

[ 51 Feb. 27, 1973 1 1 TI-IERMOSTATIC DEVICE AND MEANS FOR MOUNTING SAME [75] lnventors: John Pringle, Elizabeth Vale; Guillermo Eugene Pecker, Elizabeth,

[21] App1.No.: 86,959

Related US. Application Data [62] Division of Ser. No. 836,354, June 25, 1969, Pat. No.

337/112, 337, 338, 339, 354, 363, 380, 398, 414; 339/64 R, 64 M, 93 R, 93 C, 93 L, 125 R, 125 C, 126 R, 126 J, 126 RS [56] References Cited UNITED STATES PATENTS 2,641,667 6/1953 Shivers 337/398 X 3,562,692 2/1971 Bletz et a1 337/380 X 3,446,467 5/1969 Bailey et al. .J. 200/168 C 3,157,768 11/1964 Ladd et a1. ..337/380 3,215,873 11/1965 Kruger et a1. .....337/380 UX 2,289,863 7/1942 Batcheller ..200/168 C X 2,538,080 1/1951 Bolesky ..337/354 X 3,164,701 1/1965 Kirchhubel ..337/354 X 2,987,919 6/1961 Kirby ..337/380 X FOREIGN PATENTS OR APPLICATIONS 286,193 8/1965 Australia ..337/363 Primary Examiner-George Harris Assistant Examiner-F. E. Bell Attorney-Harold Senine, Edward J. Connors, Jr., John A. Haug, James P. McAndrews and Gerald B. Epstein [5 7] ABSTRACT A thermostatic device including a housing containing a bimetallic disc or strip which engages a cruciform shaped member, the cross arm of which engages a pair of pins which bear against leaf spring-type movable contact arms while the stem of the cruciform shaped member can form reset means providing a simple means for resetting the disc. Means for mounting the thermostatic device include a plate supporting a plurality of springs, each spring in turn urging a housing of the thermostatic device in a direction away from the plate of the device so that when the plate is secured to a surface the temperature of which is to be sensed, the springs urge the thermostatic housing into contact with the surface.

5 Claims, 8 Drawing Figures TIIERMOSTATIC DEVICE AND MEANS FOR MOUNTING SAME This is a division of application Ser. No. 836,354, filed June 25, 1969, now U.S. Pat. No. 3,609,622 which issued Sept. 28, 1971.

This invention relates to an assembly for a thermostat. I

In some circumstances there is a need for a double pole single throw thermostat, so that both lines of a device, a heater for example, can be isolated from the electrical source. According to one type of prior art thermostat, a bridge member interconnects a pair of transverse bridge members which carry contacts thereon co-operable with fixed contacts, the transverse bridge members being spring loaded by means of heli- I cal wire springs. However, these, are subject to certain failings, one of the main problems being the difficulty of obtaining a substantially simultaneous break of the contacts, so that one contact will tend to pit much more than the other. A second objection is that the device described is unnecessarily complex, and yet a third objection is that the cost of the contacts (which are usually of silver or other expensive material) is high because of the use of four contacts in a single switch. The instant invention overcomes the above-noted shortcomings and accordingly comprises the apparatusv hereinafter described, the scope of the invention being indicated in the following claims.

It is an object of the present invention to provide a two pole single throw thermostat having contacts which break simultaneously upon actuation of a thermostatic disc. Another object is the provision of a device which is relatively inexpensive, easy to assemble and of a relatively simple, uncomplicated nature, yet, reliable in operation and easily calibrated. Yet another object is the provision of a thermostatic assembly comprising a plurality of thermostatic switches each of which is in firm thermal contact with a surface, the temperature of which is to be sensed.

In the accompanying drawings in which one of the various possible embodiments of the invention is illustrated,

FIG. 1 is a top plan view of a device made according to the present invention with the cover removed;

FIG. 2 is a bottom plan view of the FIG. 1 device with the thermostatic disc and disc retaining cap removed;

FIG. 3 is a cross sectional elevation taken on lines 3-3 of FIG. I but including the cover, disc and cap;

FIG. 4 is a cross sectional elevation taken on lines 4-4 of FIG. 3, also including the cover, disc and cap;

FIG. 5 is a plan view of an assembly showing the ther mostatic device mounted on a support plate;

FIG. 6 is a front elevation of the FIG. 5 assembly;

FIG. 7 is a side elevation of the FIG. 5 assembly; and

FIG. 8 is a plan view of the support plate shown in FIGS. 54.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Turning now to the drawings, and especially FIGS. 5- 8, support plate 10 is substantially rectangular in form but has a pair of parallel opposite upturned flanges, 11, 12, the plate being provided with a pair of openings l4, 16, through which is positioned cylindrically shaped disc retaining cups 20, respectively, of disc type thermostats. It will be understood that more than two openings could be provided if it were desirable to mount more thermostatic switches. Support plate 10 is provided with two pairs of apertures a, a and b, b for each of the thermostats, each pair of apertures having extending between it a wire or leaf spring 18 which engagesan out-turned flange 24 on the disc retaining cap 20of the thermostat. Spring 18 then urges the thermostat disc retaining cap through the opening so that when the support plate 10 is clamped to a surface (not shown) which is to be sensed, the discretaining caps are urged by the respective springs into contact with the surface with a pressure which is a function of the deflection of the springs and can therefore be maintained within accurately defined limits. Reference may be had to FIG. 7 wherein flange 24 is shown in dotted lines showing the movement possible for such adjust-. ment. Face 38 of the disc retaining cap being adjacent to the disc constitutes the sensing medium, and since this will be urged into contact with the surface the temperature of which is to be sensedv by spring means 18 it follows that the disc will tend to occupy a position with a minimum air gap. If desired, for even quicker response to temperature changes, an aperture may be provided in face 38 to facilitate heat transfer from the surface to be sensed to disc 34.

The two switches are interconnected by a small bus bar 26 which in this embodiment is of L-shape and which is of small thickness so that differential move -v ment can take place between the two housings of the two thermostats. This arrangement then makes possible a simple assembly wherein a single contact single throw thermostat 30 can be used for normal control of a heat-.. ing means while the double contact single throw thermostat 32 can be used for a safety means which will throw out of circuit both lines leading to an element for example. The double contact thermostat can conveniently be of the type which, having snapped open circuit cannot be placed back into circuit except by depression of a reset button. i

The double contact single throw thermostat in this embodiment incorporates a number of improvements over previous thermostats. This thermostat is a disc operated thermostat wherein a concave disc 34 is retained in a disc retaining cap 20 which is of cylindrical form having a stepped portion 36 near a flat face 38 and adjacent cylindrical walls 40 which terminate in flared flange 25 and outwardly extending radial flange 24 at the mouth of the cap. Indexing groove means 55 may conveniently be provided in flange 25 to facilitate assembly. The disc is in contact with the top end 42 of a stern of a cruciform shaped member 44, the bottom end 46 projecting through cover 66 and constituting a reset button.

- The cross portion 48a, 48b of the cruciform shaped member 44 engages the upper ends of a pair of matched pins 52a, 52b which are freely slidable in respective apertures 54a, 54b, the lower ends of the pins engaging leaves of leaf spring type movable con-. tact arms 56a, 56b respectively. These arms have on each a contact 57a, 57b respectively which engages and disengages a corresponding fixed contact 58a, 58b in housing 50. The movable distal ends of the arms, however, carry silver or other low resistance metal contact members 57a, 57b which engage corresponding fixed contact members 58a, 58b respectively on the housing,

and the two conductors are broken each by a mating contact as the switch operates. By utilizing the matched pin arrangement it becomes possible to get substantially simultaneous opening of the two contacts, and this in turn greatly reduces the damage to contacts. Adjustment is achieved by merely changing the length of the pins. Alternative adjustment can be made by bending the leaf spring members by biasing overlying terminal members 60a, 60b respectively mounted in rectangular parallelopiped base 62 of housing 50. Further, stationary contact members 61a, 61b which mount stationary contacts 58a, 58b respectively, can be bent to effect desired calibration. Similarly, the dimension between the upper end of the stem part of the cruciform member and the upper ends of the pins can be exactly adjusted by having matched pins which are of length chosen to suit a particular switch. Cover 66 of electrically insulating material encloses the switch area.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above apparatus without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A thermostat assembly comprising:

a mounting plate having a plurality of switch receiving openings, a thermostatic switch for each opening having a cup shaped member mounted on the plate projecting through the respective opening and slidable therein and separate means biasing each thermostatic switch in a direction through the opening in the mounting plate thereby permitting adjustment of the position of each thermostatic switch when the plate is attached to a surface to insure optimum thermal contact with the surface, the temperature of which is to be sensed.

2. An assembly as defined in claim 1 in which an outwardly extending flange is provided on the cup shaped member and having an outer diameter larger than the diameter of the respective opening, the flange acting as a stop limiting the movement of the switch through the respective opening.

3. An assembly as defined in claim 1 in which two pair of apertures are provided in the plate for each switch receiving opening and spring means are connected between apertures of each pair and the spring means are biased against the cup shaped member.

4. An assembly as defined in claim 3 in which the spring means includes a generally V-shaped wire member having two free ends, the free ends being bent over in U-shaped fashion and inserted through apertures and locked therein.

5. An assembly as defined in claim 1 in which the thermostatic switches are electrically connected to each other by a flexible bus bar to permit relative movement of the switches. 

1. A thermostat assembly comprising: a mounting plate having a plurality of switch receiving openings, a thermostatic switch for each opening having a cup shaped member mounted on the plate projecting through the respective opening and slidable therein and separate means biasing each thermostatic switch in a direction through the opening in the mounting plate thereby permitting adjustment of the position of each thermostatic switch when the plate is attached to a surface to insure optimum thermal contact with the surface, the temperature of which is to be sensed.
 2. An assembly as defined in claim 1 in which an outwardly extending flange is provided on the cup shaped member and having an outer diameter larger than the diameter of the respective opening, the flange acting as a stop limiting the movement of the switch through the respective opening.
 3. An assembly as defined in claim 1 in which two pair of apertures are provided in the plate for each switch receiving opening and spring means are connected between apertures of each pair and the spring means are biased against the cup shaped member.
 4. An assembly as defined in claim 3 in which the spring means includes a generally V-shaped wire member having two free ends, the free ends being bent over in U-shaped fashion and inserted through apertures and locked therein.
 5. An assembly as defined in claim 1 in which the thermostatic switches are electrically connected to each other by a flexible bus bar to permit relative movement of the switches. 